Use yes yes instead of printf yes to pass option to pecl
Updated README

* Had missed @tddewey as a contributor, added
* Added contribution instructions for develop branch
* Update Vagrant version to 1.1.2
Go through full installation of WordPress default site

Rather than leave the site hanging for details, configure it and install it. This does require moving this section of code down below the service restart area so that mysql is available for wp-cli to use.

Next, we'll see what we can do about getting this data from a project config file